Software Design And Implementation Of Underwater Acoustic Communication System For Submarine Buoy Data Transmission

The ocean is rich in natural resources,and continuous and real-time acquisition of deepsea observation data plays an important role in the development of marine resources.In order to acquire and transmit sensor data such as the temperature and pressure of the subsea wellhead during offshore oil development in real time,a single-carrier underwater acoustic communication system for submersibles and surface drilling platforms is designed,and the embedded software of the system is implemented.The system uses directional transceivers and displacers to suppress multipath interference caused by sound reflections from the sea floor,sea surface,and other drilling platform structures.Since the submersible target is to be placed under water for a long time,the system is designed with two working modes of low-power on-duty detection and underwater acoustic communication.According to the application scenario of submarine data transmission underwater acoustic communication machine,design the overall scheme of the system and determine the system parameters.In this paper,the actual noise collection and analysis of the environmental noise distribution of the waters near the submersible and the drilling platform facilitate the selection of the communication frequency band.By comparing different communication characteristics,single-carrier communication is selected as the system communication system.Through system simulation experiments on single-carrier time-domain equalization technology,it is found that the performance of adaptive equalization RLS algorithm is better than LMS.Fractional interval decision feedback equalizer can effectively compensate the channel,and adding phase-locked loop can compensate random phase.Finally,the fractionally spaced recursive least squares decision feedback equalizer with embedded phase-locked loop is used to eliminate inter-symbol interference.Since the submersible underwater acoustic machine needs to be placed under water for a long time,an on-duty detection mode needs to be added.The detection principle is to estimate the signal frequency of the prior signal.When the adaptive Notch filter is used to detect the CW pulse signal,it can achieve the purpose of wake-up.In this paper,the response characteristics of the Notch filter to the CW signal are simulated and analyzed,and an algorithm implementation is implemented on the STM32.Then completed the development of the driver for the underlying data transmission of the underwater acoustic communicator necessary for real-time processing.This paper implements a single-carrier underwater acoustic communication algorithm on the TMS320C6655 DSP,and uses a fractionally spaced recursive least squares decision feedback equalizer with embedded phase-locked loop to eliminate inter-symbol interference.In order to achieve real-time processing,real-time processing technologies such as FFT calculation,linear convolution,superposition and addition are used,and EDMA data transmission,reasonable allocation of DSP memory,and use of standard library functions are used to optimize DSP programs,which greatly reduces DSP.Computing time,the final test proves that the communicator meets the real-time processing requirements.Finally,the function and stability of the submersible underwater acoustic communicator were verified through laboratory electric joint adjustment,pool test and Songhua Lake field test data processing.The test results show that the submersible underwater acoustic communicator software can work normally,with good stability and satisfactory performance.Design requirements.